Can Mustard Oil sub in for Caiziyou?

Short answer: Kind of, but I wouldn't go out of my way for it.

Long answer: I know that when we cook Sichuan food... our insistence on using Caiziyou, a virgin cold-pressed rapeseed oil, can sorta feel like it's bordering on the sadistic.

Here's an oil that's almost completely unavailable in the West, which's where ~70% of our viewers are based out of.  In the United States, it was banned back in the 60s due health concerns over its erucic acid content... there was some research that showed that erucic acid could be damaging to the heart when delivered at high doses to lab animals (recent research's called into question those findings, but hey, institutional momentum and all).

Rapeseed's pretty cheap though, so in the 70s a pair of researchers in Manitoba were able to effectively take out the erucic acid from Rapeseed oil (along with all of its taste) to get a cheap, neutral oil that could be used for cooking. They called this Canadian Low Acid Oil - i.e. 'Canola Oil'.

Meanwhile, in China people just kept on chugging along using Rapeseed Oil (In Mandarin, Caiziyou) - in particular in the Sichuan and Guizhou provinces.  

It's got a pretty distinctive taste and smell - walk into a little family-run restaurant in Sichuan and one of the first things that hits your nose is the smell of the rapeseed oil.  And whenever me and Steph go into a Sichuan restaurant in Shenzhen, one of our little heuristics to know whether its authentic or not is whether we can smell the rapeseed oil wafting in from the kitchen.

There's just something about that pungent, slightly bitter oil that seems to go really well with the flavors of Sichuan cookery.  Is it imperative to use? No, it's a secondary or tertiary flavor at its core.  But frying up some Sichuan food without rapeseed oil'd be a bit akin to frying up some Italian food without olive oil.

So it's a bit of a dilemma.  I don't wanna toss out a recipe that the vast majority of people can't cook, but at the same time I don't wanna assume what people can't source.  Maybe someone watching's Chinese, or an expat in China.  Maybe it's available in Malaysia/Singapore/Philippines/E. Asia (~15% of our audience). Maybe they got a hookup with one of those boutique virgin rapeseed oil manufacturers abroad, I dunno.  

Our goal's always been to try to communicate how to make a dish almost exactly how you'd find it at a tasty restaurant in China (we're not professional chefs and don't always get 100% there, but that's what we work towards). So do we handwave away the rapeseed oil or not?  Our solution's been to use the oil but in the same breath mention that you could also use peanut oil.

It's still not ideal, because if you're obsessive like me you might get that nagging feeling that the dish still isn't completely 'Sichuan'.

Enter: Indian Mustard Seed Oil

I forget when exactly, but a commenter once pointed out that Indian Mustard Seed Oil (i.e. the cooking oil, not the 'volatile oil of mustard') also faced the same ban in the USA due to Erucic Acid content.  I wasn't familiar with the oil, but it piqued my curiosity and I looked it up.

The visual was striking.  Here was an oil that looked almost exactly like the rapeseed oil that's used in Sichuan cooking. And Indian grocers seem to take advantage of a little loophole that allows em to sell the Mustard oil so long at they say it's 'for topical use only' (wink, wink)... so it's available in the West.

Then doing a quick search regarding rapeseed oil in Chinese, sitting right there on the top of Baidu Baike was this sentence staring at me in the face:

"菜籽油就是我们俗称的菜油，又叫油菜籽油、香菜油、芸苔油、香油、芥花油…" (emphasis mine)

That is, Caiziyou (rapeseed oil) is called a number of different things, one of them being... 'mustard' oil.

Of course, in my understanding (my Chinese ain't exactly the greatest) that term "芥花" can refer to the mustard plant, or it can refer to a number of things in the genus Brassicaceae (of which rapeseed's a member).  Still, I thought it could be a decent lead... and only one way to find out for sure, right? 

And after a little bit of searching, we found a shop of Taobao that sold Indian ingredients. Grabbed a bottle, and it just came in the mail an hour ago.

The verdict?

So, as you can see from the pic above, the color was identical to Sichuan caiziyou. "Awesome", I thought.  

But then as soon as I opened the bottle, the Indian mustard seed oil had a distinctly different smell from the rapeseed oil. Put a bit of each on a spoon and did a little taste test.

The first taste that hits ya is almost the same - there's this kinda funky, slightly bitter thing going on.  But then the Indian Mustard Seed Oil gives ya a nose hit that's extremely reminiscent of, well... mustard.

They're different.  They're not direct subs.  

I'll try cooking with both sometime to see how the taste is after cooking... my gut feeling's that the nose hit'd become a bit more subtle after cooking and it'd prolly still go pretty well with Sichuan food, but I can't be sure right now. (I'll update this post once I get around to testing that)

So given that Peanut Oil has the advantage of being available basically everywhere, we'll keep that as our 'sub of choice' for now.

Sigh.